• Environmental 101 for Homeowners – Part 3

  • By: Bill Leedham, P.Geo., CESA 

    In my last blog I discussed concerns related to asbestos, lead and Urea Formaldehyde Foam Insulation (UFFI) that you could find in a residential home. This month we’ll look at the issues and safety concerns related to mould, radon gas and Polychlorinated Biphenyls (PCB).    

    Mould and Water Infiltration
    For mould to grow, it requires a food source like wood, drywall, cellulose, etc.; favourable temperature and humidity conditions; and a source of water such as a leaking roof, building envelope failures, or excessive humidity.  Mould is very common, and you will find it in many homes and buildings – look in your window sills, or around tubs and showers and you will often see small patches of mould. Where it becomes problematic is when you get extensive areas of mould growth, or encounter some of the more toxic varieties like aspergillus or stachybotrys.  For some people, like the elderly, the very young, or those who are sick or have compromised immune systems mould can be very dangerous to their health, sometimes even deadly.  Minor occurrences of the less toxic varieties can often be dealt with by the homeowner with a variety of readily available commercial products. However, extensive and/or toxic mould problems will require identification and abatement by a mould expert. It is also very important to investigate and fix the underlying water infiltration problem; otherwise the mould will just return.

    Radon Gas
    Radon is a naturally occurring, odourless and colourless gas originating as a by-product of the breakdown of radioactive minerals, such as uranium-bearing bedrock. It is also a carcinogen and one of the leading causes of lung cancer.  Radon is encountered everywhere, usually at lower, background levels which are not harmful.  The problem occurs when it is found at elevated concentrations that are considered to be unsafe. According to Health Canada the current guideline for radon in indoor air for dwellings is 200 Becquerels per cubic metre (200 Bq/m3), while in the US, the Environmental Protection Agency considers radon levels above 4 picocuries/litre (pCi/L) to be unsafe (4 pCi/L equals 148 Bq/m3).  The presence of elevated levels of radon in a home is a function of local bedrock geology, the type and thickness of overburden soils, the presence of potential entry points for migration of radon gas (e.g. cracks or gaps in basement floors or foundations, presence of sumps or wells), and the efficiency of the homes ventilation system.  There are numerous home test kits available, as well as consultants who can test the radon level in your home. When elevated, unsafe levels are encountered, they should be addressed, usually accomplished by sealing entry points and increasing the ventilation and air circulation.  Federal and provincial/state governments, as well as private databases providers such as ERIS can provide maps of reported radon levels in your area.

    Polychlorinated Biphenyls (PCB) in Electrical Equipment
    Polychlorinated biphenyls (PCBs) are a group of over 200 chemicals based on a combination of chlorine and biphenyl, a derivative of benzene.  PCBs were produced in North America from 1929 until 1977, when their manufacture was banned in order to limit distribution and control disposal due to concerns over its potential as a carcinogen and its effect on reproductive processes. Older buildings constructed or renovated prior to the manufacturing ban could potentially contain PCBs in the cooling oils of fluorescent and high-intensity light ballasts, capacitors or other electrical equipment. The presence of PCBs in lamp ballasts can often be confirmed by checking the date of production, name of the manufacturer and their production code against reference documents published by Environment Canada. This should never be done by dismantling a live, energized light or ballast. Large scale re-lamping or updates may require pre-planning to determine PCB status of the fixtures so that proper and legal removal, storage and disposal procedures can be implemented.

    As previously noted, these comments are provided for general information purposes only; you should always follow all applicable regulations and safety protocols, and if you are in doubt or have concerns please consult a qualified expert.


    Bill Leedham, P. Geo., CESA

    Bill is the Head Instructor and Course Developer for the Associated Environmental Site Assessors of Canada (www.aesac.ca); and the founder and President of Down 2 Earth Environmental Services Inc. You can contact Bill at info@down2earthenvironmental.ca